A newlywed couple was captured on video walking to board a helicopter that crashed moments later, killing them on the night of their wedding.

"We sent them off with something that they will remember," said Jacob Martinez, who helped with the couple's send-off and filmed the video. "It chokes me up because I saw them get in the helicopter, which seemed to be fine."

The newlyweds, William Troy Byler and Bailee Raye Ackerman Byler, both 24, took off just after midnight Sunday. The helicopter crashed minutes after they left their family and friends.

"I can't put into words how you go from a happy ending to a tragedy," Martinez said, KENS reports.

The pilot, 76-year-old pilot Gerald Green Lawrence, was also killed. Family friends said he was a U.S. Army captain and a Vietnam War veteran, according to KENS. He was an experienced pilot, said Craig Hatch, an air safety investigator with the National Transportation Safety Board (NTSB).

The cause of the crash is unclear. Investigators are assessing factors including the pilot's history, the helicopter's background and weather conditions in the area. The helicopter crashed near the city of Uvalde about 80 miles west of San Antonio.